What is the initial source of phosphorous in the phosphorous cycle?

The initial source of phosphorus in the phosphorus cycle is rocks and sediment. Phosphorus is primarily found in the form of phosphate minerals within geological formations. Over time, weathering processes release these phosphates into the soil and water systems. Unlike other biogeochemical cycles, phosphorus does not have a significant atmospheric component; it mainly cycles through the lithosphere (the earth's crust) and biosphere.

Once released from rocks and sediment, phosphates can enter plant systems, where they are taken up by plants and subsequently move through the food web. This process is crucial for the synthesis of important biological molecules such as ATP, DNA, and RNA, which are essential for life. Phosphorus does not exist in a gaseous state under natural conditions, which distinguishes its cycle from others that involve atmospheric components.